Abstract Host shifts, when a cross-species transmission of a pathogen can lead to successful infections, are the main cause of emerging infectious diseases, such as COVID-19. A complex challenge faced by the scientific community is to address the factors that determine whether the cross-species transmissions will result in spillover or sustained onwards infections. Here we review recent literature and present a perspective on current approaches we are using to understand the mechanisms underlying host shifts. We highlight the usefulness of the interactions between Drosophila species and viruses as an ideal study model. Additionally, we discuss how cross-infection experiments — when pathogens from a natural reservoir are intentionally injected in novel host species— can test the effect cross-species transmissions may have on the fitness of virus and host, and how the host phylogeny may influence this response. We also discuss experiments evaluating how cooccurrence with other viruses or the presence of the endosymbiont bacteria Wolbachia may affect the performance of new viruses in a novel host. Finally, we discuss the need of surveys of virus diversity in natural populations using next-generation sequencing technologies. In the long term, these approaches can contribute to a better understanding of the basic biology of host shifts.

中文翻译：

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宿主转移是新发传染病的原因：利用果蝇-病毒相互作用的实验方法

摘要 宿主转移（病原体的跨物种传播可导致成功感染）是新出现的传染病（如 COVID-19）的主要原因。科学界面临的一个复杂挑战是解决决定跨物种传播是否会导致溢出或持续感染的因素。在这里，我们回顾了最近的文献，并对我们用来理解宿主转移机制的当前方法提出了看法。我们强调果蝇物种和病毒之间的相互作用作为理想研究模型的有用性。此外，我们还讨论了交叉感染实验（当来自天然宿主的病原体被有意注入新的宿主物种时）如何测试跨物种传播对病毒和宿主的适应性的影响，以及宿主系统发育如何影响这种影响回复。我们还讨论了评估与其他病毒共存或内共生细菌沃尔巴克氏体的存在如何影响新病毒在新宿主中的表现的实验。最后，我们讨论了使用下一代测序技术调查自然群体中病毒多样性的必要性。从长远来看，这些方法可以有助于更好地理解宿主转变的基本生物学。